You are not gonna like my post.
The tractor got stuffed into the quonset shed because like scores of engines I have seen 'rebuilt' on this board the owner didn't do it right and it hammered noisely. So he shoved into a corner, dropped off the radar on this board and subsequently perished with the tractor being a disapointment at the end.
That's the bad news. The good news is the whole top end might be fresh and all you gotta do is regrind the crank and make the bottom good.
That's a lot cheaper than a full rebuild.
Dunno what your circumstances are - if you bought a pig in a poke or you aint bought it yet or the tin and paint and tires are nice but the motor hammers. Depending...
I wouldn't despise a tractor that hammers but I would adjust the price to suit.
I bought a tractor once that had the crank broke clean in half. It was a very good tractor otherwise but the crank dumped the sale price and I bought it accordingly.